Employees from Costco, Walmart, and Target share their worst horror stories -- and they'll make you rethink how you act when you shop

Anat Givon/AP Images Walmart,Target, andCostco employees — as well as workers at all retail stores — sometimes come up against pretty difficult customers. Business Insider spoke with a number of retail workers about some memorable and negative experiences they've had on the job. Their stories just go to show that it's always a good idea to be courteous while shopping. Walmart, Target, and Costco employees have seen some pretty gnarly things on the job. Many retail workers, in fact, can proba...